Power wheelchairs are used by disabled individuals in order to move around in comfort and relative ease. Indeed, these wheelchairs have improved throughout the years to provide numerous features that provide additional comfort to individuals.
A power wheelchair typically includes a base having wheels. The base supports a seat assembly. The individual controls operation of the wheelchair through a control interface, such as a joystick, typically positioned on an armrest of the seat assembly. The control interface is in electrical communication with a processing system that is also connected to motors that drive the wheels, a steering mechanism, and the like. The processing system generally controls overall operation of all powered aspects of the wheelchair.
A wheelchair also includes legrests in which an individual positions his/her legs. Many legrests are adjustable such that they may be moved through various positions.
FIGS. 1 and 2 illustrate isometric side and front views, respectively, of a conventional power wheelchair 10. As shown in FIGS. 1 and 2, the wheelchair 10 includes a seat assembly 12 and a legrest assembly 14 connected to the seat assembly 12. The legrest assembly 14 includes a central column 16 extending from and proximate to a front edge of the seat assembly 12. Calf supports 18 are positioned on either side of the central column 16 below the seat assembly 12. Footrests 20 extend from an end of the column 16 that is distal from the seat assembly 12. As shown, in the normal position, the footrests 20 are generally parallel with the seating area of the seat assembly 12, while the calf supports 18 and central column 16 are generally perpendicular to the seating area.
The legrest assembly 14 may be adjusted so that it may rotate upward about an area where it connects to the seat assembly 12. That is, a proximal end of the central column 16 is pivotally connected to the seat assembly 12.
In order to adjust the legrest assembly 14, an actuator 22 may be engaged to move the legrest assembly 14. As shown in FIG. 1, the actuator 22 is positioned behind the legrest assembly 14. The actuator 22 is typically secured to the central column 16.
The position of the actuator 22 behind and on the legrest assembly 14 provides a bulky assembly. The actuator 22 adds weight to the legrest assembly 14. As such, when moving the legrest assembly 14, the actuator 22 uses energy sufficient to move both the legrest assembly 14 and the actuator 22 itself. The added weight and bulk, as well as the center of gravity, may cause adjustment of the legrest assembly to be uneven and halting.
FIG. 3 illustrates an isometric side view of the conventional power wheelchair 10 in which the legrest assembly 14 is outwardly adjusted. As shown in FIG. 3, the actuator 22, which is attached to the legrest assembly 14, moves the legrest assembly 14 and the actuator 22 in the direction of arc A. The legrest assembly 14 pivotally moves in the direction of arc A about a hinged interface that connects the legrest assembly 14 to the seat assembly 12. An individual may adjust the legrest assembly 14 through various positions, such as through a control interface.
As shown in FIGS. 1-3, the central column 16 of the legrest assembly 14 is straight. When the legrest assembly 14 is adjusted upwardly in the direction of arc A, the straight central column 16 typically causes the force of the weight of the individual legs to concentrate onto the heels that are supported by the footrests 20. As the legrest assembly 14 continues to move upward in the direction of arc A, the concentration of the weight on the heels typically increases, which may cause the individual seated in the wheelchair to experience discomfort.
Additionally, conventional wheelchair assemblies such as shown in FIGS. 1-3 provide a limited range of adjustability. Also, in order to adjust the length of the individual legrests of the legrest assembly 14, a separate and distinct mechanism, such as a hinge mechanism 24 positioned behind each legrest is used. However, the hinge mechanism 24 on each legrest adds even more weight and bulk to the legrest assembly 14.